Step stool



FIG. 1 is a perspective view of the step stool, incorporating the new design;

FIG. 2 is a front elevational view, the rear elevational view being a mirror image;

FIG. 3 is a left side elevational view thereof; and

FIG. 4 is a right side elevational view thereof,

FIG. 5 is a top view of the step stool; and,

FIG. 6 is a bottom view of the step stool. 

The ornamental design for the step stool, as shown and described. 